Giant electroresistive ferroelectric diode on 2DEG

Abstract

Manipulation of electrons in a solid through transmitting, storing, and switching is the fundamental basis for the microelectronic devices. Recently, the electroresistance effect in the ferroelectric capacitors has provided a novel way to modulate the electron transport by polarization reversal. Here, we demonstrate a giant electroresistive ferroelectric diode integrating a ferroelectric capacitor into two-dimensional electron gas (2DEG) at oxide interface. As a model system, we fabricate an epitaxial Au/Pb(Zr 0.2 Ti 0.8)O 3 /LaAlO 3 /SrTiO 3 heterostructure, where 2DEG is formed at LaAlO 3 /SrTiO 3 interface. This device functions as a two-terminal, non-volatile memory of 1 diode-1 resistor with a large I + /I - ratio (>10 8 at ±6 V) and I on /I off ratio (>10 7). This is attributed to not only Schottky barrier modulation at metal/ferroelectric interface by polarization reversal but also the field-effect metalinsulator transition of 2DEG. Moreover, using this heterostructure, we can demonstrate a memristive behavior for an artificial synapse memory, where the resistance can be continuously tuned by partial polarization switching, and the electrons are only unidirectionally transmitted. Beyond non-volatile memory and logic devices, our results will provide new opportunities to emerging electronic devices such as multifunctional nanoelectronics and neuromorphic electronics.